-LRB- CNN -RRB- -- Brazilian public notary Claudia do Nascimento Domingues set off a firestorm by granting Brazil 's first civil union to a trio , an act so unprecedented that there is n't a word for it in Portuguese .

Uniao poliafetiva is the label she created . `` Polyfidelitous union '' is her best guess in English .

The relationship involves three professionals in their 30s -- one man and two women -- who , she says , live together , love one another as equals and are like any other non-married cohabiting couple -- except they are three .

What Domingues did was legally register the trio as a `` stable union , '' a civil union that extends all of the benefits of marriage , though there is debate about what rights the threesome will actually enjoy . In short , it recognizes the trio as a family entity for public legal purposes .

Domingues has not released the identities of the three .

But not all are embracing the unique alliance .

`` This union is void of any legality , '' said Regina Beatriz Tavares da Silva , head of the family law committee of a lawyers ' association in Sao Paulo .

Brazilian law defines marriage as a union between two people , so it is impossible for a civil union of three to be granted the rights of a marriage of two .

`` It goes directly against the constitution , '' da Silva said . `` Monogamy is defined as relations between two , not three or four or five . ''

The first-of-its-kind civil union has led to an outcry from religious groups , too . Those who fear the `` slipperly slope '' feel the ground moving underneath their feet .

`` The institution of family can not be defended with the approval of actions that seek to distort its definition , '' the religious , conservative Plinio Correa de Oliveira Institute said in a statement . `` The purpose of this -LRB- union -RRB- is not to build families , but to destroy them . ''

The controversial civil union `` is proof that there is a plurality of familiar relations , though not all deserve judicial or legal standing , '' Rolf Madaleno , director of the Brazilian Institute for Family Law , said in a statement . `` The action carried out does not provide protections and does not confer rights . ''

In his opinion , the legal action in question does nothing more than reaffirm that the trio in question believes that they are a trio .

Domingues , 39 , argues that they deserve some benefits . They live together in Rio de Janeiro , they share a bank account , and they want protection in case of separation or death , she said .

Brazil is known for its progressive social policies and openness , as reflected in the status conferred to the trio , though the country is stereotyped , too . While Brazil appears to be a permissive place , it is also a a country where more than 86 % of the population identifies as Catholic or evangelical .

There was a similar outcry when `` stable unions '' between same-sex couples were allowed for the first time . The country 's supreme court ruled that a gay couple in a civil union had the same rights as a married heterosexual couple , but there is debate about whether such rights can be extended to a trio .

But to Domingues , a public notary in the city of Tupa in Sao Paulo state , there is nothing preventing nontraditional relationships from being granted `` stable union '' status .

The trio considers themselves a family and is entitled to be seen as such in the public record , Domingues said .

`` By registering them , I only confirmed that they recognize themselves as a family , '' she said . `` I do n't confer rights to them . That is up to a judge to decide . ''

The civil union was actually granted three months ago , but news of it only spread this week .

Da Silva called the civil union `` deceitful , '' a runaround to grant status to a polygamous relationship .

Such relationships are n't new ; they just have n't been recognized , Domingues said .

She says that she simply put her stamp of approval on a relationship that was surfing on a wave of cultural currents , but it was no coincidence that the request landed on her desk .

The trio from Rio , having been rejected by other public notaries , found their way rural Sao Paulo state and to Domingues because she is a student of polyfidelitous relationships -- ones involving more than two partners , but where there is fidelity between the members .

Formerly an IT manager , Domingues now is a doctoral student at the University of Sao Paulo , studying family law .

Her dissertation , she said , is about `` how you can love more than one person at the same time . '' Her research looks at cultures , places , sociology , anthropology , religion and the history of family and intimate relationships in Brazil .

Through mutual friends , the trio found Domingues and traveled more than 600 miles from Rio , into the interior of Sao Paulo state , to Tupa .

Domingues does n't hesitate to call herself married , though she and her husband are bound by a `` stable union '' and not a civil marriage . Her husband works with her as a deputy public notary .

`` We have had all the reactions you can imagine , '' she said .

Other polyfidelitous groups have reached out to her seeking the same civil union status .

Domingues is studying the cases of a quintet -LRB- two men and three women -RRB- and another trio -LRB- one woman and two men -RRB- .

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In Brazil , a notary has granted a civil union to unite a man and two women

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The public notary who approved the status says they have the right to be a family

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Others say it is a violation of the constitution and destroys families

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The notary is now studying unions for another trio and for a quintet